Fuel intake for two-cycle engines



Jufy 17,1928. 1,677,604

' A. B. STREETER FUEL INTAKE FOR TWO-CYCLE ENGINES Filed March 7, I925 n at) a high pressure air line,

' of such. finely Patented July 17, 1928.

eai'rso STATES PATENT .o1=,r 1cs.v

ALBERT B; STBEETER, YORK, N. Y. ASSI IIGNOR 'Il IO DUAL MOTORS CORPORA- TION, OE 1TEW YORK, N. Y., A CORPORATIONYOF DELAWARE.

:I-NTAKE FOR :rwobyoma mvonms.

. Application 'fil'ed March], 1925. A Serial No. 13,671.

The invention relatesin general to an internal combustion engine of the typein which the smallerend of a differential piston moves in an explosion chamber andthe larger end moves in a pump chamber, and in which air under pressure either from the pump chamber-associatedtherewith, or from the pump chamber of a companion unit, is discharged into the explosion-chamber, for scavenging the same of its refuse gas and the invention relates specifically to an improved form of two cycle engine.

. The present disclosure'more particularly relates to the'fuel line, or more properly to constituting part of the fuel feeding apparatusilea'ding to the explosion chamber. The present disclosure may be consideredas one unit of a, two-cylinder engine of the type outlined, in which the high pressure air from the p'urnp of one unit is supplied to the explosionchamber of the other unit and otherwise this application may be regarded as a companion case with my co-pending applicationv entitled Air compressor for internalfcombustion engines Serial No. 12,990 filed ,March'3. 1925. L

In two-cycle engines of the type herein disclosed it is a usual practice to inject'into the explosion chamber gaseous fuel from a carburetor and to introduce this gaseous fuel at the forward end of the space in the cylinder traversed by the piston on itseompression stroke. Instead of using gaseous fuel it is proposed in the present instance to inject into the chamber a charge ofliquid fuel in a finely divided state, andto propel the same by a charge of combustion support- 1- ed in my co-pending application Serial No. 642,- 465, filed May 31, 1923, entitled Fuel metering valve.

In general the present. disclosure features a greater eiiiciency in utilizing the charge divided liquid particles than is possible where the charge is fed through the head of the combustion chamber ,as' is disclosed in the said pending application;

This phase of the invention is attained by positioning the combined fuel and combusf tionsupporting air intake portin' the side of the cylinderand in spaced relation to the opposite ends of the path of travel ofthe end of the piston travelling in the explosion chamber.

ing air, all as is more definitely descri Another object of the invention is to provide for a cooling of the fuel intake port to avoid detonation or premature explos on atthis point'and for the fuel metering valve associated therewith, and incidentally to relieve thisvalve from high back pres sures and from the hi h temperatured heat generated" in the chamber during the initial periods offthe combustion. At the same t1me the invention features the utilization of the hot water in the water acket for the purpose of preheating, at least. to same extent; of the fuel particles as they are ejected into the explosion chamber.

'Another object of the invention is to pro vide for a timed control of the high-pressure, I

combustion-supporting air fed to the meterng valve and to produce the same economi; cally; and momentarily at the instant when it is needed. Accordingly the present disclo sure features the avoidance of this high pressure air on the line except when actually i needed. I Vanousother objects and advantages of the invention will be in-part obvious from an inspection of the accompanying drawings and 1n part Wlll be more 'fullyset forth in the followingparticular description of one form of device embodying my invention, and the invention also consists in certain new and novel features of construction and combinat'ion of parts hereinafter set forth and claimed. 1 p f p c i In the accompanying drawings The figure is a view in vertical tlon of an engine cylinder unit disclosing one of the duplicated units of apreferred embodiment of the invention. In the followingdes'cription and in the claims partslwill be identified by specific names for convenience of expression but they are intended to be as generic in their application to similar parts as the art will permit.

In the drawing there is shown an engine casing 10 which is preferably one of the pair ofcylinder structures shown" in the coinpanion application as the units are identical the detailed description of one will be equally applicableto the other. The upper portion of the cyin'der is of relatively small internal diameter and forms an explosion chamber 11. The-lower part of this cylinder is of greater, diameter than the diameter of the explosion chamber and forms a pump chamber 12. There is disclosed a differential area axial sec-* llti spaced about one side of the cylinder.

thirds of its compression stroke.

piston 13, with its small head 14 workingin the explosion chamber and with its large head 15 working in the pump cylinder to form an. air compresser. The upper end of the explosion chamber is closed by a head 16, positioned centrally in which is a spark plug 17. This head as well as the-wall'forming the cylindrical part of the explosion chamber is waterfiacketed forthe entire'length of the piston displacement in the explosion ch amber exceptfor the ports hereinafter described. This water jacketing will have the usual effect of keeping the explosion engine cool but the metering valve and fuel inlet tube hereinfater described will be heated sufliciently during the operation of the engine to materially raise the temperature of the liquid fuel ejected into the chamber. The illustrated structure will'thus tend to preheat the liquid'parti'cles at the instant they are blown into the explosion chamber.

At the forward or lower end of the cylinderll the wall thereof is provided with a series of exhaust ports 18, circumferentigly pposite the exhaust ports are a similar line of air scavenging inlet ports 19, supplied with relatively low pressure air from a reservoir 20,in turn suppliedfromthe.pump cylinder 12 while acting as alow-pressure air condenser in a manner more particularly described in the companion application.

The advanced end 23.of the piston in its n'iovementtowards the closed end or head 16 1 of the cylinder travels from a point'slightly below its position uncovering the ports 18 and 19 to a point indicated approximately by the .line 21, in spaced relation to the underside of'the head to form a' shallow eX: plosion space orclearance 22 between the advancedend of the .piston and the underside of the closed head'lti.

A combined fuel and air inlet port124 opens into the explosion .chamber ata point intermediate the'length of the movement of the piston end 23. In a preferredphysical embodiment of the inventionthis fuel port is disposed. at a point spaced fromthe closed head about two and one-half times the mean depth of the explosion space 22. Different- 1y defined this inlet port is located at'the pointreached by the advanced end 23 of the piston when it has travelled about two- This port is formed at the inner end of a bore 25 centered in a tube26 which extends acrossthe hot water space 27 between the water-jacket forming walls of the cylinder 11.

The fuel leading to the bore 25 is con trolled by a fuel metering device 28, contained in a valve casing 29, preferably formed as a casting integral with the'side of the cylinder 11. The casing is provided with vertically extending air conduits 30,

' open at top and bottom and designed to assist in keeping the valve casing cool. The

fuel metering device includes a rotary valve 31 of the cylinder type, and is provided with av measuring pocket '32 extending diametrically therethrough.

In the case of the dual cylinder constructionthe-rod"forming the valve 31 also forms external atmosphere A spray valve 37 controls the "passage offuel through the port 34 anctotlierwise itis understood that this metering"device corresponds in general to the disclosure in:1ny Patent No.'1',609,386, Dec.7, 1926.

, Air underhigh pressure is supplied to. the

inlet 33"th1'ougha pipe 38 leading'from the upper end of the pump chamber 12. Airis required at'the metering'valveionly at the instant when'the'measuringpocket 32 is in line connecting the bore 25'with'theair' inlet 33. lVhile an air pressureis needed at this time it is required only for'thisinstant-that the air be "underextremely :high pressure so as to 'blast the liquidparticles through the-port24 into the combustion cylinder. The present "disclosure therefore features an; arrangement by means of which the supply of air is out off between the'pump cylinder and the pipe38until'the large head 15 of the piston is moving into its final 'air compressing position. Preferablythe pipe 38Ileads to a manifold 46 tozwhich also'leads the pipe indicated diagrammatically ,at 47 corresponding tothe. pipe 38 from the pump ofthe other cylinder unit. The manifold opens to the "inlets. 33 of both ,metering devices, so t-hatthere isa'blast of'air into the manifold as the pistons successively reachthe endsof'their 'air compression strokes. The two'meterin'gvalve are so timed in their rotati'on. that one is opened to admitthe air from the; manifold as the'piston in'the other compressorreaches the" limit of its compression stroke.

In order to close the pipe 38 from the as-- valverod,.a portion of which'is provided.

with a diametrically extending passageway tolformthe valve 39. Portions of this valve rod are utilized to control the low pressure airfrom the pumpcylinder"into the reservoir, as more particularly described in my Ill) 38 and-passageway 43 extendsthrough the adjacent pump cylinder 12.. wall of the pump cylinder from the entrance of V the passageway which limits the travel of the piston head 15 on its compression stroke, is slightlyrecessed longitudinally to provide a-by-passage way 45aroundthe advanced edge of the head 15. From this construction it will be seen that even after the piston head 15 passes the inner end of ,the 7 air compressor is open to the valve 39 to the limit of the piston movement. At the instant the air compressor is exerting maximum pressure on the contained air, this air is open to the valve so that when the valve is rotated into position to open the-air supply to the pipe 38 a source of high pressure all ated or the other explosion chamber.

A hot target or bafile extends upwardly from the end 23 of the piston and is disposed to be moved with the piston intothe path of the charge ofincoming full particles to assist in vaporizing the same and to turn the stream towards and into the combustion space 22. i

In operation it will be apparent that as the small piston end 14 moves upward towards the fuel inlet port it will be compressing pure fresh air taken in through the ports 19. Incidentally during this initial movement of the piston the large end 15 of the piston will be supplying low pressure air to the scavenging air reservoir 20, as more particularly defined in the companion application.

As the piston advances from its position closing the scavenging and exhaust ports it acts to compress the air trapped in the explosion chamber. metering valve 31 is turning towards and past its position receiving its charge of finely divided liquid fuel and moving the same towards its position aligned with the high pressure air inlet 33. Just prior to the time the upper end of the piston reaches the fuel port 2 1 the metering valve has reached the horizontal position in which the same 1s opened to the explosion chamber. At this instant the air valve of the other unit and corresponding to the valve 39 controlling the high pressure air line is opened and a blast of air under the maximum available pressure is directed through the metering valveto project the liquid particles into the combustion chamber. fie projecting upwardly from the hot end of wall at theupperportion of the The upper portion of 43 to the'shoulder 14 passageway 43, the

is immediately available to the associ- During this time the By this time the bafi the piston has advanced into the path of the.-

into the explosion space 22 where it can be fired by the spark plug on the advanceof the piston into its proper firing location.

. As the piston move-s past the fuel inlet 1 valve on the compression stroke it will, of course, close this port but this closing is immaterial for by this time the meterin valve has rotated into position to shut off thesup-J ply of fuel and air. Just prior to the instant of-maximum compression the charge is fired, the piston moves on its working stroke and at the end of the stroke uncovers the air scavenging and exhaust ports, thus permitting the cylinder to bescavenged of its refuse gas as is well known in this art. The cycle of operation is thus repeated, each explosion chamber alternately receiving and firing its contained charge.

'By means of a device of this character it is possible to obtain a higher efliciency than has been possible heretofore in engines of this type.

The construction disclosed features a relatively cool engine and apparently the locating of the fuel metering valve awa from the hot head facilitates accuracy in the control of the liquid fuel in such a way as would not be possible with the fuel if it were in its usual gaseous condition. A greater efiiciency in operation has been attained by placing the fuel intake in the side than was obtained when it was disposed in the hizad at the place now occupiedby the spark p ug. r

The present disclosure provides a fuel feeding system which utilizes high pressure air and yet does not require expensive forms of packing and valves for holding the pressure. Thisis apparently due to the fact that the high pressure is not retained, but is used as soon as generated. The use of two valves tends to minimize leakage and insures the til the air line is open to the explosionchamber. It is within the scope of the disclosure where only one cylinder unit is desired, to have the metering valve Supplied with high pressure air from the compressor positioned below the same as disclosed in the drawings, making the necessary changes in the periodicity of the valves 31 and 39 or utilizing the pipe 38 as a small reservoir.

lVhile I have shown and described, and have pointed out in the annexed claims, certain novel features of my invention, it will be understood that various omissions, substitutions and changes in the form and de tails otthe device illustrated and in its op eration may be made by those skilled in the are Without departing from the spirit of the invention. I

Having thus described my invention, I claim 2 In an internal combustion engine, the combination of an explosionchamber and a pump chamber, a di'll erential piston having its smaller head Working in the explosion chamber and its larger head Working in the pump chamber, said combustion chamber provided With a fuel inlet port intermediate its length and controlled by the smaller head of the piston, a fuel metering device including a rotary valvet'or measuring the fuel supplied to said inlet port, means for supplying fuel to said valve, a high pressure air conduit leading from the pump chamber adjacent its high pressure end to said metering device to blow from the'me'te'ring device the fuel charge measured by the'valve and to eject the same into the explosion chamber, a rotary valve controlling the air flow 1n said conduit, said rotaryval'ves being operatively connected to operate in timed relation to the piston travel to cause the high pressure air to eject the fuel into the explosion chamber When the fuel inlet port is uncov ALBERT B. STREETER. 

